1. Field of the Invention
The present invention relates to a structure of a brush holder used in a dynamo-electric machine.
2. Discussion of Background
FIGS. 12a and 12b illustrate a conventional brush holder for a dynamo-electric machine. FIG. 12a is a plan view of the brush holder, wherein components of the brush holder are assembled. FIG. 12b is a plan view, whereby a part of the components is disassembled.
In FIGS. 12a and 12b, numerical reference 21 designates a brush holder base; numerical reference 22 designates a brush; numerical reference 23 designates a metallic brush holder; numerical reference 24 designates a plate; numerical reference 25 designates a pigtail; numerical reference 26 designates a terminal plate; and numerical reference 27 designates a spring.
FIG. 13 is a perspective view of the metallic brush holder 23 and the plate 24 illustrating a state of assembling these. FIG. 14 is a side cross-sectional view of the metallic brush holder 23 and the plate 24.
The terminal plate 26 is formed by insert-molding, wherein after locating the plate 24 in the brush holder base 21, the metallic brush holder 23 is fixed by caulking. After assembling the metallic brush holder 23, the spring 27 is assembled inside the metallic brush holder 23, and thereafter the brush 22 is assembled. A position where the terminal plate 26 and the pigtail 25 are welded is a side of the metallic brush holder 23.
Because the conventional brush holder is constructed as described above, the terminal plate 26 is connected to the pigtail on a right side or a left side of the brush 22. Therefore, sliding of the brush was affected depending on a state of the pigtail, whereby there were problems that an operating noise of a motor and ripples of torque were increased, and that, in a dynamo-electric machine rotatable in both directions, differences of torques, of the numbers of revolutions, of operating noises, and of ripples of torques were different with respect to the rotating directions.